Multiple contact diaphragm relay



' vSept-1,1970 SJWOODHEAD I 3,526,864

MULT PLE CONTACT DIAPHRAGM RELAY Filed Oct. 11, 1968 s Sheets-Sheet 1 I In vvvv 0r h! 5; wao'oumo Y I. I Attorney Sept. 1.11970 I-L-SQWOODHEAD' 3,526,854

MULTIPLE CONTACT DIAPHRAGM RELAY Filed on. 11, 1968 v L s Sheets Sheet'2 Sept. 1 1970- .H'.s. wooDHEA D 3,526,864

- MULTIPLE CONTACT DIAPHRAGM RELAY Filed ad. IL, 1968 v S Sheets -Sheet s Zw /J/ 30 o0 a zozooxo United States Patent US. Cl. 335-202 23 Claims ABSTRACT OF THE DISCLOSURE An electromagnetic change-over-relay comprising two contact sets having a laminar armature for each of said contact sets and including multiple-pole polarized versions.

This invention relates to electromagnetic change-over relays.

According to the invention an electromagnetic changeover relay includes two or more contact sets, each contact set including on opposite sides of a laminar armature a make contact and a break contact, the contact sets being situated within a sealed contact enclosure through one Wall of which are sealed ferromagnetic members forming the make contacts of the contact sets each of which members in co-operation with its associated armature held within said enclosure in spaced parallel relationship with the plane of said wall, forms part of a magnetic circuit associated with each contact set, and including a ferromagnetic yoke outside the enclosure which links said magnetic circuits with a ferromagnetic core which is common to all said magnetic circuits, the energization of which causes the armatures to be urged away from their associated break contacts and towards their associated make contacts hence actuating the relay.

The Wall through which the ferromagnetic members forming the make contacts are sealed preferably consists of a non-magnetic and electrically insulating material such as glass, the ferromagnetic members, the glass wall, and a metal rim embracing the periphery of the glass wall forming a multiple element glass-to-metal seal assembly.

The foregoing and other features of the invention will be evident from the following description of two preferred forms of electromagnetic relay embodying the invention, a change-over relay and a polarised change-over relay.

The description refers to the accompanying drawings in which:

FIG. 1 shows a longitudinal section of the relay,

FIG. 2 shows a sectioned view of the relay in the plane marked II--II in FIG. 1,

FIG. 3 shows a longitudinal section of part of a relay incorporating a modification to make the relay a polarised relay, and

FIG. 4 shows a sectioned view of the polarised relay in the plane marked IVIV in FIG. 3.

The relay shown in the drawings can be considered as composed of two principal parts, a multiple-contact sealed switch assembly and the associated external magnetic circuit and energizing coil.

The switch assembly indicated generally at 1 consists of an enclosure formed by two glass to metal seal assemblies comprising flat circular glass walls 2 and 3 having sealed thereto rims 4 and 5, separated by an annular spacing piece 6. The rim 5 as will be explained hereinafter forms part of the magnetic circuit of the relay and therefore is made of ferromagnetic material such as mild steel.

Within the enclosure are found four contact sets, each set comprising a make contact 7 and a break contact 8 on opposite sides of a laminar armature 9. The make con- 3,526,864 Patented Sept. 1, 1970 "ice tacts 7 are provided by four short lengths of nickel iron tube sealed through the glass wall 3. Eight similarly shaped tubes 10 are sealed through the other glass wall 2, four of these tubes, 10a, hold the break contacts 8 which are in the form of precious metal contact rivets counter-bored to leave annular contact-making surfaces, while the other four tubes, 10b, provide anchorages for the armatures 9 holding them in spaced parallel relationship with the plane of the glass wall 3. The armatures 9, which in their unstressed state are flat, are made from a resilient ferromagnetic metal such as an alloy of nickeliron laminae shaped as shown in FIG. 2 each armature having anchorage area 12 by which it is attached to its anchorage tube 10a, and this anchorage area 12 being linked by two arms 13 to a tongue 14 on which is provided the contact making areas, which co-operate with the armatures associated make and break contacts. The magnetic circuit by which the armatures 9 are switched includes the armatures themselves and also includes the make contacts 7 and the rim 5 and therefore all these components must be made of ferromagnetic material, the shapes and relative positions of these components being designed so that the movement of the contact making areas between the make contact 7 and the break contact 8 is substantially rectilinear. In order to improve the electrical conductivity and the contact properties of the armatures and the make contacts these may be plated with a layer of silver. This silver layer may itself be covered at least in the region of the contact making surfaces with a layer of a suitable noble metal such as a palladium.

When the anchorage areas 12 of the armatures 9 are secured to their anchorage tubes 10a the plane of these anchorage areas intersects their associated break contacts 8 so that even while the relay is not actuated the armatures are strained thus providing the necessary contact pressure between the armatures and their break contacts.

Outside the enclosure the make contact tubes protrude through apertures in a ferromagnetic yoke 17 in the form of a disc which magnetically links the individual make contacts to a common ferromagnetic core 18, however they are electrically insulated from the yoke by insulating washers 19 contained in the apertures through which they pass.

The core 18 of the relay is surrounded by the operating winding 20 of the relay which is wound on an insulating former 21, and this is held in position by an end plate 22 of magnetic material secured to the core 18. The outside diameter of the former 21 and the winding 20 are made smaller than that of the rim 5 so that an outer cover 23 can be sprung into position over the rim -5 and the end plate 22.

This cover 23 is also made of ferromagnetic material and completes the magnetic circuit of the relay which can be traced from the core 18 through the yoke 17, the make contacts 7, the armatures 9, the rim 5, the outer cover 23, the end plate 22 and around to the magnetic core member again. It will be seen that the magnetic circuit associated with each armature includes two gaps, that between the make contact 7 and the tongue 14 of the armature 9 and that between this tongue and the rim 5. These gaps are magnetically in series but the attractive forces upon the tongue upon energization of the relay are mechanically in parallel, or in other words additive.

Connection to the relay contacts and to the operating winding is made by sets of terminal pins 25 and 26 respectively. These pins are protected from accidental contact with the body of the relay by means of insulating washers 27, or alternatively may be individually sheathed in insulating sleeves. The terminal pins are shown bent so that they all project from one side of the relay, and their spacing may be such as to comply with the normal track spacing for printed circuit assemblies. The small physical dimensions of a relaya practical realization of the arrangement shown in FIGS. 1 and 2 being approximately 1.3 inches long and 0.6 inch in diameterrendering it particularly suitable for such applications.

It should be noted that the construction of the enclosure of the switch assembly is such as to allow the manufacture of the principal seals, the glass-to-metal seals, as a first step in manufacture, and thus the relatively high temperatures necessary for making such seals cannot have a deleterious effect upon items such as the diaphragm and the operating winding which are added at a later stage. The final step in the manufacture of the switch assembly can be made the sealing of the distance piece 6, the rims 4 and 5, and this can conveniently be effected by using the technique of projection welding in conjunction with a distance piece 6 formed with welding rings on the surfaces abutting the rims.

A variation of the above described relay is given by an 8 contact set relay. This relay is distinguished from the first described relay in that it comprises two multiplecontact sealed switch assemblies, one mounted at each end of the magnetic core member. Hence the relay is as above described with reference to FIG. 1 except that the end plate 22 is dispensed with and its place taken by a second yoke and a second multiple-contact sealed switch assembly similar to the first described ones indicated by the reference numerals 17 and 1 respectively. The outer cover 23 in this relay magnetically links the rim to its counterpart in the second switch assembly, the two assemblies being in series with each other and the magnetic core member.

A second variation of the first described relay is given by the 4 contact set polarised magnetically latching relay, and features of this relay are illustrated in FIGS. 3 and 4. For the purposes of this specification the term polarised magnetically latching relay is defined to mean a relay in which the magnetic flux threading the armature assumes a value dependent upon whichever of the two switched states it is in, which value is appropriate for it to be retained in that position while the operating winding is not energised. This relay is identical with the first described relay illustrated in FIGS. 1 and 2 except that the core extends further beyond the end of the operating 'winding former remote from the switch assembly, and this extension includes a section which is a permanent magnet. There is also included fitted around the core, an arcuate collar made of ferromagnetic material. Referring to FIGS. 3 and 4 the switch assembly is indicated at 1, that part of the core 18 which is a permanent magnet is indicated at 30 and the arcuate collar is indicated at 31. The remainder of the integers bear the same index numerals as hereinbefore defined with reference to FIGS. 1 and 2.

This relay has two magnetic circuits linking the permanent magnet 30. The principal magnetic circuit threads the operating winding 20, threads the whole of the core 18, the yoke 17, the :make contacts armatures and rim of the switch assembly 1, the outer cover 23 and the end plate 22. The arcuate collar 31 which is made of mild steel provides a subsidiary circuit for the permanent magnet which shunts the switch assembly 1, this circuit threads the collar 31, part of the outer cover 23 and the end plate 22. The reluctance of the subsidiary circuit is primarilydetermined by the air gap between the collar 31 and the outer cover 23. Since both these components are arcuate in cross sections the value of this reluctance can be adjusted to a desired value within a limited range of values by the rotation of the collar with respect to the outer cover. (FIG. 4 shows the collar in the position giving minimum reluctance.) In this embodiment it is preferred to arrange the magnetic components so that when the armatures are in contact with their break contacts and the operating winding is not energised there is more magnetic flux threading the collar than the total flux threading the four armatures.

In the construction of this relay the use of a magnetic shunt provided by the collar 31 providing a subsidiary magnet circuit for the permanent magnet but shunting the operating winding, the armatures and make contacts, gives rise to a number of advantages. Firstly it enables the adjustment, during manufacture of the relay, of the flux threading the armatures. Secondly it shunts the permanent magnet from the demagnetising field produced when the operating winding is energised in such a way as to reduce the flux threading the armatures in order to transfer them from contact with their make contacts to contact with their break contacts. Thirdly it lowers hte reluctance of the magnetic circuit seen by the operating winding, thereby enabling a smaller number of ampere turns to cause the relay armatures to change-over. And fourthly it causes a greater ditference in the amount of flux threading the armatures as compared between their two positions, for after they are switched to make contact with their make contacts some of the flux from the permanent magnet is switched from threading the shunt t0 threading the armatures and this results in an improvement of the latching properties of the relay.

It is to be understood that the foregoing description of specific examples of this invention is made by way of example only and is not to be considered as a limitation on its scope.

I claim:

1. An electromagnetic change-over relay comprising two contact sets, a laminar armature for each contact set, each contact set including on opposite sides of the associated laminar armature a make contact and a break contact, a sealed contact enclosure enveloping the contact sets, said enclosure including two flat circular walls sealed to two annular rims of ferromagnetic material and an annular spacing piece sealed between the rims, said enclosure providing a magnetic flux path through its ferromagnetic elements, ferromagnetic members sealed through one of the flat Walls of the enclosure to form the make contacts of the contact sets and parts of a plurality of magnetic circuits, each laminar armature lying in spaced parallel relationship with the plane of said wall to form a part of a magnetic circuit in association with each contact set, a ferromagnetic yoke outside the enclosure to link each of the magnetic circuits with a ferromagnetic core in common with all said magnetic circuits, said ferromag netic core responding to energization of a core winding to cause the laminar armatures to be urged away from the associated break contacts and towards associated make contacts, thereby actuating the relay.

2. A relay as claimed in claim 1 which in addition is a polarized relay including in the magnetic circuits associated with the contact sets a permanent magnet which is common to these circuits.

3. A relay as claimed in claim 1 wherein the wall of the enclosure through which the said ferromagnetic members are sealed consists of a non-magnetic and electrically insulating material.

4. A relay as claimed in claim 3 wherein the material of the wall through which the said magnetic members are sealed is glass.

5. A relay as claimed in claim 1 wherein the break contacts are mounted on supports sealed through the wall of the enclosure opposite said wall through which are sealed the ferromagnetic members.

6. A relay as claimed in'claim 1 wherein the armatures are anchored to posts sealed through the wall of the enclosure opposite said wall through which are sealed the ferromagnetic members.

7. A relay as claimed in claim 6 wherein the material of the wall of the enclosure opposite said one wall through which are sealed the ferromagnetic members is glass.

8. A relay as claimed in claim 6 wherein the make contacts are electrically insulated from the yoke and are each provided with an independent electrical terminal.

9. A relay as claimed in claim 6 wherein each armature is shaped to provide a tongue carrying a contact making area, the tongue being linked by two arms to an anchorage area.

10. A relay as claimed in claim 9 wherein the contact surfaces co-operating with the make and break contacts are provided by the surfaces of the armatures.

11. A relay as claimed in claim 10 wherein each armature is shaped to provide for substantially rectilinear motion of its contact surface between its associated make and break contacts.

12. A relay as claimed in claim 11 wherein the contact surfaces of the armature have thereon a layer of a noble metal.

13. A relay as claimed in claim 11 wherein the contact surfaces of the make contacts have thereon a layer of noble metal.

14. A relay as claimed in claim 1 wherein the contact surfaces of the make contacts are annuli.

15. A relay as claimed in claim 1 wherein the contact surfaces of the break contacts are annuli.

16. A relay as claimed in claim 1 wherein a ferromagnetic core extends from the side of the yoke remote from the sealed enclosure and is surrounded by an operating winding.

17. A relay as claimed in claim 16 wherein the core extends beyond the side of the operating winding remote from the yoke and includes in the portion of its length so extending a permanent magnet.

18. A relay as claimed in claim 17 wherein a principal magnetic circuit including the permanent magnet, the part of the core surrounded by the operating winding, and the armatures is shunted by a ferromagnetic shunt providing a link in a subsidiary magnetic circuit which includes the permanent magnet but shunts the part of the core surrounded by the operating winding and the armatures.

19. A relay as claimed in claim 18 wherein the shunt is an arcuate collar on the core.

20. A relay as claimed in claim 16 including a ferromagnetic outer cover embracing the winding providing a magnetic link in the magnetic circuit threading the operating winding.

21. A relay as claimed in claim 20 including a ferromagnetic end plate providing a magnetic link between the outer cover and the end of the core remote from the sealed enclosure.

22. A relay as claimed in claimed 16 wherein the end of the core remote from the yoke terminates in a second yoke associated with a second contact enclosure containing therein two or more contact sets, which second yoke and second contact enclosure together with contact sets contained therein are identical with the yoke, contact enclosure and contact sets as defined in any preceding claim.

23. A relay as claimed in claim 22 including a ferromagnetic outer cover embracing the winding and providing a magnetic link between the two contact enclosures.

References Cited UNITED STATES PATENTS 3,324,432 6/1967 Ridlel' 33515 1 3,331,040 7/ 1967 Woodhead 335-196 3,388,354 6/1968 Myatt 335-151 GEORGE HARRIS, Primary Examiner H. BROOME, Assistant Examiner 

